Blowout preventers are used extensively throughout the oil and gas industry in order to prevent undesirable fluid flow from the wellbore through the wellhead. The two categories of blowout preventers that are most prevalent are ram blowout preventers and annular blowout preventers. Blowout preventer stacks frequently utilize both types, typically with at least one annular blowout preventer stacked above several ram blowout preventers. Accordingly, typical blowout preventers may include a main body to which various types of ram units may be attached. The ram units in ram blowout preventers allow for both the shearing of the drill pipe and the sealing of the blowout preventer. Typically, a blowout preventer stack may be secured to a wellhead and may provide a safe means for sealing the well in the event of a system failure.
In a typical blowout preventer, a ram bonnet assembly may be attached to the main body using a number of high tensile bolts or studs. The bolts or studs are positioned through a flange of the bonnet assembly to couple the bonnet assembly to the body. In some blowout preventers, the bonnet assembly can include a bonnet door that is hinged to the body. This allows the bonnet assembly to be held in a desired position relative to the body while the bolts or studs are connected. In addition, the hinged bonnet assembly allows for easy access to the inside of the ram unit. It is desirable to provide a hinged bonnet assembly that enables easy maintenance for parts of the blowout preventer that might become worn or damaged.